1. Field of the Invention
The present invention relates to a semiconductor wafer processing, LCD display glass substrate processing, magnetic memory disc processing and other devices fabricated from thin film processes and more specifically to a substrate which can sense and transmit processing conditions.
2. Discussion of the Related Art
The fabrication of an integrated circuit, display or disc memory generally employs numerous processing steps. Each process step must be carefully monitored in order to provide an operational device. Throughout the imaging process, deposition and growth process, etching and masking process, etc., it is critical, for example, that temperature, gas flow, vacuum pressure, chemical gas or plasma composition and exposure distance be carefully controlled during each step. Careful attention to the various processing conditions involved in each step is a requirement of optimal semiconductor or thin film processes. Any deviation from optimal processing conditions may cause the ensuing integrated circuit or device to perform at a substandard level or, worse yet, fail completely.
Within a processing chamber, processing conditions vary. The variations in processing conditions such as temperature, gas flow rate and/or gas composition greatly affect the formation and thus the performance of the integrated circuit. Using a substrate to measure the processing conditions that is of the same or similar material as the integrated circuit or other device provides the most accurate measure of the conditions because the thermal conductivity of the substrate is the same as the actual circuits that will be processed. Gradients and variations exist throughout the chamber for virtually all process conditions. These gradients therefore also exist across the surface of a substrate. In order to precisely control processing conditions at the wafer, it is critical that measurements be taken upon the wafer and the readings be available in real time to an automated control system or operator so that the optimization of the chamber processing conditions can be readily achieved. Processing conditions include any parameter used to control semiconductor or other device manufacture or any condition a manufacturer would desire to monitor.
Within the processing chamber a robot head transports the test wafer or substrate. One example of a device incorporating a robot head is manufactured by the TEL Corporation. The robot head can pivot. The robot head also incorporates multiple levels or hands. A first level or hand can extend out and a second level or hand can further extend out carrying a wafer. A second robot or moving platform can receive the wafer and extend it to a third holder which lowers it into the process chamber. For more information about the robot head and processing chamber, please refer to U.S. Pat. No. 5,564,889 to Araki, entitled “Semiconductor Treatment System and Method for Exchanging and Treating Substrate,” which is hereby incorporated by this reference in its entirety.